Thanks. The first step if you haven’t already done it is to load the Device Handler in the IDE. Post back if you’re not familiar.
Then in the ST app, open the device page for the dimmer. Select the 3 dot menu top right, then “Settings”. Scroll down to “AC Power Type” and set it to “Non Neutral”. Scroll down to “Switch Type” and set it to “3-way Momentary”. Back your way out.